Dental service utilization and the COVID-19 pandemic, a micro-data analysis

Background Global crises and disease pandemics, such as COVID-19, negatively affect dental care utilization by several factors, such as infection anxiety, disrupted supply chains, economic contraction, and household income reduction. Exploring the pattern of this effect can help policy makers to be prepared for future crises. The present study aimed to investigate the financial impact of COVID‐19 disruptions on dental service utilization. Methods Data on the number of dental services offered in Dental School Clinics of Tehran University of Medical Sciences was collected over a period of two years, before and after the initial COVID-19 outbreak in Iran. School of Dentistry operates two clinics; one with competitive service fees and one with subsidies. Regression analyses were performed to determine the effect of the pandemic on the number of dental services divided by dental treatment groups and these clinics. The analyses were adjusted for seasonal patterns and the capacity of the clinics. Results There was a significant drop in dental services offered in both clinics across all dental groups in the post-COVID period (on average, 77 (39.44%) fewer services per day). The majority of the procedure loss happened in the Private clinic. Adjusting for seasonal patterns and the service capacity, regression results documented 54% and 12% service loss in Private and Subsidized clinics following the pandemic, respectively. Difference-in-difference analysis documented that the Subsidized clinic performed 40% more treatments than the Private clinic in the post-COVID period. Conclusions Pandemic –reduction in dental care utilization could have long-term ramifications for the oral health of the population, and policymakers need to provide supportive packages to the affected segments of the economy to reverse this trend. Supplementary Information The online version contains supplementary material available at 10.1186/s12903-023-03740-2.

Table A1: Level of Dental Services and the Pandemic (S+P).The table presents the estimated slope coefficients for the number services offered in Dental School clinics of Tehran University of Medical Sciences by each dental treatment group and the pandemic indicator variable (COVID).The regressions also include the month-fixed effects.The sample period is from April 21, 2019, to April 21, 2021 at the daily frequency.P-values are estimated using robust standard errors (reported in parentheses).***, **, and * denote statistical significance at the 1%, 5%, and 10% p-value levels, respectively.

Fig. A1 .
Fig. A1.Service Capacity.The graph shows the histogram of the daily dental services offered in Subsidized (S) and Private (P) clinics of Tehran University of Medical Sciences by all treatment groups.The top and bottom panels present the results for the pre-COVID and post-COVID periods, respectively.The data ranges from April 21, 2019 to April, 21, 2021.

Fig. A2 .
Fig. A2.Treatments by Clinics.The graph shows the total number dental treatments offered in Subsidized (S) and Private (P) clinics of Tehran University of Medical Sciences, at the daily frequency.In addition, the fitted trend line for each group is shown.The data ranges from April 21, 2019 to April, 21, 2021.
Group j COVID t + γ m Month m t + e

Table A2 :
Level of Dental Services and the Pandemic (S).The table presents the estimated slope coefficients for the number services offered in the Subsidized (S) clinic of Tehran University of Medical Sciences by each dental treatment group and the pandemic indicator variable (COVID).The regressions also include the month-fixed effects.The sample period is from April 21, 2019, to April 21, 2021 at the daily frequency.P-values are estimated using robust standard errors (reported in parentheses).***, **, and * denote statistical significance at the 1%, 5%, and 10% p-value levels, respectively.Group j COVID t + γ m Month m t + e

Table A3 :
Level of Dental Services and the Pandemic (P).The table presents the estimated slope coefficients for the number services offered in the Private (P) clinic of Tehran University of Medical Sciences by each dental treatment group and the pandemic indicator variable (COVID).The regressions also include the month-fixed effects.Group j COVID t + γ m Month m t + e

Table A4 :
Level of Dental Services and the Pandemic (S&P).The table presents the estimated slope coefficients for the number services offered in Dental School clinics of Tehran University of Medical Sciences by each dental treatment group and the pandemic indicator variable (COVID).PRIVATE is an indicator variable that takes the value of one for the services offered by the Private clinic.The regressions also include the month-fixed effects.The sample period is from April 21, 2019, to April 21, 2021 at the daily frequency.The analysis includes the daily observations when both clinics and dental treatments are offering services.P-values are estimated using robust standard errors (reported in parentheses).***,**, and * denote statistical significance at the 1%, 5%, and 10% p-value levels, respectively.COVID t × PRIVATE Clinici + γ m Month m t + e

Table A5 :
Level of Dental Services and the Pandemic (DID test).The table presents the estimated slope coefficients for the number services offered in Dental School clinics of Tehran University of Medical Sciences by each dental treatment group and the pandemic indicator variable (COVID).PRIVATE is an indicator variable that takes the value of one for the services offered by the Private clinic.The regressions also include the month-fixed effects.The sample period is from April 21, 2019, to April 21, 2021 at the daily frequency.The analysis includes all daily observations.P-values are estimated using robust standard errors (reported in parentheses).***,**, and * denote statistical significance at the 1%, 5%, and 10% p-value levels, respectively.COVID t × PRIVATE Clinici + γ m Month m t + e

Table A6 :
Change in Dental Services and the Pandemic (S+P).The table presents the estimated slope coefficients for the percentage changes in the number of services in the post-COVID period offered in Dental School clinics of Tehran University of Medical Sciences by each dental treatment group and the pandemic indicator variable (COVID).The growth rate of services for the observations in each month is measured by the average values in the same month of the year in the pre-COVID period.The regressions also include the month-fixed effects.The sample period is from April 21, 2019, to April 21, 2021 at the daily frequency.P-values are estimated using robust standard errors (reported in parentheses).***, **, and * denote statistical significance at the 1%, 5%, and 10% p-value levels, respectively.Group j COVID t + γ m Month m t + e − 1 = α + β

Table A7 :
Change in Dental Services and the Pandemic (S).The table presents the estimated slope coefficients for the percentage changes in the number of services in the post-COVID period offered in the Subsidized (S) clinic of Tehran University of Medical Sciences by each dental treatment group and the pandemic indicator variable (COVID).The growth rate of services for the observations in each month is measured by the average values in the same month of the year in the pre-COVID period.The regressions also include the month-fixed effects.The sample period is from April 21, 2019, to April 21, 2021 at the daily frequency.P-values are estimated using robust standard errors (reported in parentheses).***, **, and * denote statistical significance at the 1%, 5%, and 10% p-value levels, respectively.Group j COVID t + γ m Month m t + e − 1 = α + β

Table A8 :
Change in Dental Services and the Pandemic (P).The table presents the estimated slope coefficients for the percentage changes in the number of services in the post-COVID period offered in the Private clinic of Tehran University of Medical Sciences by each dental treatment group and the pandemic indicator variable (COVID).The growth rate of services for the observations in each month is measured by the average values in the same month of the year in the pre-COVID period.The regressions also include the month-fixed effects.The sample period is from April 21, 2019, to April 21, 2021 at the daily frequency.P-values are estimated using robust standard errors (reported in parentheses).***, **, and * denote statistical significance at the 1%, 5%, and 10% p-value levels, respectively.Group j COVID t + γ m Month m t + e − 1 = α + β

Table A9 :
Change in Dental Services and the Pandemic (S&P).The table presents the estimated slope coefficients for the percentage changes in the number of services in the post-COVID period offered in Dental School clinics of Tehran University of Medical Sciences by each dental treatment group and the pandemic indicator variable (COVID).PRIVATE is an indicator variable that takes the value of one for the services offered by the Private clinic.The growth rate of services for the observations in each month is measured by the average values in the same month of the year in the pre-COVID period.The regressions also include the month-fixed effects.The sample period is from April 21, 2019, to April 21, 2021 at the daily frequency.The analysis includes the daily observations when both clinics and dental treatments are offering services.P-values are estimated using robust standard errors (reported in parentheses).***,**, and * denote statistical significance at the 1%, 5%, and 10% p-value levels, respectively.COVID t × PRIVATE Clinici + γ m Month m t + e

Table A10 :
Change in Dental Services and the Pandemic (DID test).The table presents the estimated slope coefficients for the percentage changes in the number of services in the post-COVID period offered in Dental School clinics of Tehran University of Medical Sciences by each dental treatment group and the pandemic indicator variable (COVID).PRIVATE is an indicator variable that takes the value of one for the services offered by the Private clinic.The growth rate of services for the observations in each month is measured by the average values in the same month of the year in the pre-COVID period.The regressions also include the month-fixed effects.The sample period is from April 21, 2019, to April 21, 2021 at the daily frequency.The analysis includes all daily observations.P-values are estimated using robust standard errors (reported in parentheses).***,**, and * denote statistical significance at the 1%, 5%, and 10% p-value levels, respectively.COVID t × PRIVATE Clinici + γ m Month m t + e

Table A11 :
Level of Relative Dental Services and the Pandemic.The table presents the estimated slope coefficients for the number of services the Subsidized clinic of Tehran University of Medical Sciences offered in excess of its Private clinic by each dental treatment group and the pandemic indicator variable (COVID).The regressions also include the month-fixed effects.The sample period is from April 21, 2019, to April 21, 2021 at the daily frequency.P-values are estimated using robust standard errors (reported in parentheses).***, **, and * denote statistical significance at the 1%, 5%, and 10% p-value levels, respectively.Group j COVID t + γ m Month m t + e

Table A12 :
Level of Relative Dental Services and the Pandemic.The table presents the estimated slope coefficients for the number of services the Subsidized clinic of Tehran University of Medical Sciences offered in excess of its Private clinic by each dental treatment group and the pandemic indicator variable (COVID).The regressions also include the month-fixed effects.The sample period is from April 21, 2019, to April 21, 2021 at the daily frequency.P-values are estimated using robust standard errors (reported in parentheses).***, **, and * denote statistical significance at the 1%, 5%, and 10% p-value levels, respectively.Group j COVID t + γ m Month m t + e